Windows users use DXVK to boost framerates, it was the solution for making Elden Ring playable it’s first month

I would say at that point the cost/reward is worth it

True, though for most game/graphics developers you're never interfacing directly with the graphics API, you'll let your chosen engine/library do the heavy lifting.

It does have the downsides of increasing the barrier to entry for custom/bespoke engines but those edge cases seem to be covered well by DXVK.